San Diego Zoo’s Hawaii Endangered Bird Conservation Program

In September, conservation practitioners and environmental educators from across the Philippines, as well as the Pacific island of Pohnpei, gathered to participate in the Island Species-Led Action (ISLA) course run by the Durrell Wildlife Conservation Trust, which was held in association with Iligan Institute of Technology, Mindanao State University, Philippines. The 10-day course was designed to teach participants proven and practical approaches to manage endangered species and habitats on islands, thereby enhancing existing knowledge and expertise and ultimately developing the local skill base and resources for conservation measures and initiatives.

In Hawaii, the native ecosystem has been decimated by a whole suite of threats—habitat destruction, introduced mammalian predators and plants, unsustainable hunting and introduced disease—resulting in the extinction of very significant numbers of native fauna and flora. But these threats are by no means unique to Hawaii. Islands have high levels of endemism, meaning a large proportion of the wildlife is unique to a specific island (or island group). But their ecosystems are fragile and very susceptible to threats, and their species particularly predisposed to extinction. This makes islands hotspots for conservation.

Based on my experiences with the San Diego Zoo’s Hawaii Endangered Bird Conservation Program and previous endeavors on the island of Mauritius, I was lucky enough to be invited to teach on the ISLA course. Having developed skills in captive propagation, reintroduction, and other fieldwork, I presented case studies and conservation techniques applicable to island ecosystems. It was hugely rewarding to share knowledge and perspectives with other conservation biologists facing similar island-focused challenges.

My fellow members of the ISLA course tutorial team were Durrell’s Jamie Copsey and Professor Carl Jones, with Dr. Olga Nuñeza, vice-chancellor of the Iligan Institute of Technology. My association with Durrell’s International Training Center goes back more than a decade, having once been a student there myself. In fact, for the past three summers, I have acted as external course director on their endangered species recovery course, based at Durrell’s headquarters on the island of Jersey in the U.K.

The warmth of the hospitality from our Philippine hosts and participants goes beyond words. But for the three international tutors, there was one other indisputable highlight: a field trip to Bukidnon Province in search of the Philippine eagle Pithecophaga jefferyi. Looking through a bird encyclopedia as a young boy, the Philippine eagle held almost mythical status; it was part of a small group of very notable bird species that I always dreamed of seeing in the flesh—due to it prominent rarity and challenge to observe—but never expected to see. After several hours of hiking along forest trails, the brief sight of an enormous, broad-winged eagle flying over the forest canopy made the flesh tingle. When we came face to face with birds at the captive breeding center of the Philippine Eagle Foundation, to say we were “awe-struck” is an understatement.

These eight new alala chicks represent 10 percent of the world's population.

To me, one of the most exciting aspects of working with the San Diego Zoo’s Hawaii Endangered Bird Conservation Program (HEBCP) is artificially incubating eggs. `Alala (or Hawaiian crow) eggs are incubated for approximately 22 days until they hatch (see Corvid Cupid). Once we pull an egg from the nest, we are able to monitor the embryo’s developmental progress by regularly candling the egg. Eventually, this enables us to identify the first step of the hatching process: the embryo’s beak pushing into the air cell. The air cell is the pocket of air at the top of the blunt end of the egg. With its beak in the air cell, the embryo’s lungs start to activate, which enables the blood to be drawn in from the vessels wrapped around the inside of the eggshell that had previously been used for gas exchange.

Just before or soon after an embryo first breaks through the eggshell (known as an external pip), we move the egg into a hatcher that is maintained at a constant temperature of 99 degrees Fahrenheit. The hatcher also needs to be very humid so that the hatching chick doesn’t dry out and stick to the membranes and residual albumen found inside the egg. Another important component of the hatching process is for the chick to know that there is a “parent bird” out there waiting for it to hatch. We simulate this by putting speakers inside the hatcher that we use to broadcast `alala vocalizations for a few minutes every hour. Periodically we also tap very gently on the eggs. The embryo often responds to these stimuli by increasing its efforts to hatch out of the egg. While some `alala embryos take up to 36 hours to hatch after the first external pip, we have been spoiled this season with some embryos hatching only 6 hours after they make their external pips. That translates into fewer sleepless nights for HEBCP staff, since externally pipped eggs require frequent monitoring throughout the night, in case we need to intervene and provide assistance.

With these efforts, the `alala flock of the HEBCP has been receiving the welcome addition of new chicks. The 2010 breeding season got off to an encouraging start, with the earliest `alala hatches in the history of the program. As of July 1, 2010, we have so far hatched 12 `alala chicks, with 11 surviving, currently ranging in age from just 1 day to 2 months. This brings the total known population of `alala up to 78 birds.

Each breeding season involves stress, sleepless nights, hard work, and occasionally even a few gray hairs for the staff of HEBCP. But more importantly, we each get the rewarding task of helping to bring `alala chicks into the world and the `alala back from the brink of extinction.

Jeremy Hodges is a research coordinator with the San Diego Zoo’s Hawaii Endangered Bird Conservation Program. Read his previous post, Spring Cleaning in Hawaii.

Red Rocket (#14) and NU (#30), our two oldest nene (or Hawaiian geese), have been around long enough to see plenty of changes. Both birds were hatched in the wild and came to live at the Maui Bird Conservation Center (MBCC) in 1987 and 1992 respectively. They were moved in 1996 from mosquito-proof buildings with concrete floors to outdoor pens with grass. Now they have brand-spanking-new pens, luxury suites of the nene world! Not only were the old pens past their use-by date, but they will soon be demolished to make space for new ‘alala (or Hawaiian crow) aviaries that will be constructed this fall (see Corvid Cupid).

An aerial view shows the new pens for nene.

Aaron’s Construction recently finished building four sturdy new pens to house our nene. Each pen comes furnished with a tented mesh “roof,” so adults and their goslings can remain fully flighted and ready for release. They have also been constructed of strong wire mesh walls to keep rats and mongoose at bay, and, of course, each pen comes equipped with shelter, hoses for easy cleaning, food stations, and pools for bathing and keeping cool in the summertime. We will keep a total of four pairs of nene, with our sights set on a goal of producing at least 75 birds over the next five years; all will be released at Haleakala Ranch as part of the Hawaii Division of Forestry and Wildlife’s commitment to this safe harbor agreement.

Roy Newton offers a traditional Hawaiian blessing for the nene.

Following local cultural practice, and to prepare our nene for what we hope will be a fruitful life, required the help of a Hawaiian minister. On June 3, Roy Newton visited MBCC to deliver a Hawaiian/English blessing over the new pens and anointed each with a mixture of water and Hawaiian salt so that any animal entering them will be protected. NU and Rocket moved into their new home directly after the blessing, along with the rest of the nene flock at MBCC.

We hope NU and Rocket will be around to see many more happy changes. In the meantime, they are ready to offer a warm welcome and plenty of aloha spirit to MBCC visitors during Nene Awareness Day (mark your calendars for September 26)! Read about last year’s Nene Awareness Day.

Lisa watches Crow TV, monitoring the reproductive behavior of `alala at the nest.

As corvids, `alala (Hawaiian crows) have a wide range of complex behaviors, particularly when it comes to the art of courtship (see ‘Alala: We’re Getting Closer). Being so intelligent, each individual bird has its own personality, likes, and dislikes. This also applies to their interactions and relationships with birds of the opposite sex.

Now this may sound rather anthropomorphic, but in actual fact we soon learn to recognize the different behavioral patterns of individual birds, which helps to define them as individuals and as breeding pairs.

Each `alala is given a name (See Naming `Alala Chicks), which is a very valuable tool for enabling us to remember these patterns of behavior as well as breeding history, husbandry, and veterinary ailments, even though we record all information formally with studbook number as well. (With 70-plus birds in the captive flock, a name is so much easier to remember than a number.)

When it comes to selecting pairs, genetic management of our shallow gene pool is vitally important to maximize long-term genetic diversity. Being extinct in the wild, there is no hope for bringing new genes into the `alala population. Breeding birds are first selected according to their mean kinship (MK) to the rest of the flock. Put simply, a bird with few relatives in the flock has a low MK, so it is a genetically valuable bird.

A bird’s potential mate is selected according to many factors, most importantly the pair’s inbreeding coefficient (IC). The IC is a measure of how closely related the two individuals in a pair are, based on the chance of their offspring inheriting identical genes from each parent. If the pair is closely related (e.g. mother-son), the IC is high, which is bad news for any offspring that may be produced. To make matters more complex, the interbreeding within the limited `alala gene pool over so many generations now means that birds are actually more closely related than they may initially appear. When selecting pairs, we always try to minimize the IC between the two birds, thereby increasing our chances of producing healthy offspring.

It is not just genetic factors that are important in selecting pairs. In several cases, young pairs that select each other from within a flock of youngsters, not surprisingly, often have the best compatibility…with total lack of regard for the genetic calculations.

Sometimes, a genetically well-matched pairing does not necessarily guarantee good compatibility between the individual birds. So, in some extreme cases, the only contribution that the male makes to the nesting process is a series of copulations during socializations that we call “conjugal visits.” In other cases, the pair may be very compatible, but the male’s exuberance for the breeding season overwhelms the female at the nest. In these cases, we temporarily remove the male so that the female can have time at the nest on her own.

How do we keep track of all of these important genetic and behavioral profiles? Check back soon for Corvid Cupid (part 2).